10 months post endoscopic brow lift, my left brow has failed due to an extra strong muscle. How common is this?

Although I do perform endoscopic brow lifts, I only do so in select patients. In general I find open brow lifts are much more reliable both in terms of the longevity of the lift was well as the ability to address the forehead muscles. The fact that your surgeon want to correct the one side with an open procedure speaks to that fact. I think that the resulting scar is minimal and negligible if performed appropriately. The open approach allows for better release of the bone along the brow, direct visualization of the muscles and better fixation of the higher brow position. The results last for many years.

Brow lifts by any method can regress. The usual cause of failure is inadequate release of tissues at the orbital rim especially with a subperiosteal dissection as is done with the endoscopic brow lift. I prefer open procedures esoecially if there is a high hairline or there has been haurline elevation from an endoscopic browlift. The trichophytic hairline scar is rrarely detectible. However the open approach always has sensation changes in the scalp that go away with time.